U.S. patent application number 09/834335 was filed with the patent office on 2002-01-17 for method for removing butyl groups from butyl phenol compounds.
Invention is credited to Ekawa, Kenji, Higashi, Mitsuhiro, Yao, Kazuhiko.
Application Number | 20020007092 09/834335 |
Document ID | / |
Family ID | 18624451 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020007092 |
Kind Code |
A1 |
Yao, Kazuhiko ; et
al. |
January 17, 2002 |
Method for removing butyl groups from butyl phenol compounds
Abstract
By bringing a p-butylphenol compound or m-butylphenol compound
in the gas phase into contact with a solid acid catalyst, i.e., a
silica-alumina catalyst or alumina catalyst while heating, butyl
groups are removed from the butylphenol compound and at the same
time, highly purified isobutylene is recovered.
Inventors: |
Yao, Kazuhiko; (Wakayama,
JP) ; Higashi, Mitsuhiro; (Wakayama, JP) ;
Ekawa, Kenji; (Wakayama, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
620 NEWPORT CENTER DRIVE
SIXTEENTH FLOOR
NEWPORT BEACH
CA
92660
US
|
Family ID: |
18624451 |
Appl. No.: |
09/834335 |
Filed: |
April 13, 2001 |
Current U.S.
Class: |
568/716 |
Current CPC
Class: |
C07C 37/50 20130101;
C07C 37/50 20130101; C07C 39/07 20130101; C07C 39/06 20130101; C07C
37/50 20130101 |
Class at
Publication: |
568/716 |
International
Class: |
C07C 039/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 2000 |
JP |
2000-112249 |
Claims
What is claimed is:
1. A method for removing butyl group from a butylphenol compound,
comprising contacting a butylphenol compound in a gas phase with a
solid acid catalyst under heat to remove butyl group from the
butylphenol compound.
2. The method according to claim 1, wherein the butylphenol
compound is p-t-butylphenol or m-t-butylphenol.
3. The method according to claim 1, further comprising recovering
butylene from which butyl group is removed.
4. The method according to claim 3, wherein the recovered bulylene
is purified isobutylene.
5. The method according to claim 1, wherein the solid acid catalyst
is a silica-alumina catalyst or alumina catalyst.
6. The method according to claim 1, wherein the butylphenol
compound is a butylphenol compound present in a reaction system
where 3,3',5,5'-tetra-tert-butylbiphenol is subjected to removal of
butyl group.
7. The method according to claim 1, wherein the removal of butyl
group is conducted at a temperature of 200.degree. C.-500.degree.
C.
8. The method according to claim 1, further comprising adding water
to the butylphenol compound for decoking.
9. The method according to claim 1, wherein the butylphenol
compound is contacted with the solid acid catalyst at a liquid head
space velocity (LHSV) of 0.01-10 g/cc/hr.
10. The method according to claim 3, wherein the butylene has a
purity of 95-100%.
11. The method according to claim 1, wherein the removal of butyl
group is conducted at a butyl group removal rate of 80-95%.
12. The method according to claim 1, wherein butyl group at any
position is removed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for removing butyl
groups from a butylphenol compound.
[0003] More specifically, the present invention relates to a method
for removing butyl groups from a butylphenol compound using a solid
acid catalyst in the gas phase.
[0004] 2. Description of the Related Art
[0005] Methods for removing butyl groups from butylphenol compounds
to produce phenol compounds are conventionally known. For example,
Japanese Patent Publication No. S49-39659 describes a method for
isolating and recovering highly purified m-tert-butylphenol, in
which a silica alumina solid acid catalyst is added to a mixture of
m- and p-tert-phenols, or a mixture of o-, m- and p-tert-phenols,
in the liquid phase to remove butyl groups from o- and
p-tert-butylphenols. Japanese Patent Application Laid-open
S52-71422 discloses a method for producing highly purified mcresol
and p-cresol, in which in order to isolate m-cresol and p-cresol
from a mixture of m- and p-cresols, said mixture is reacted with
isobutylene to obtain corresponding butylated cresols, after which
these cresols are isolated by distillation, and butyl groups are
removed from the resulting mono- and di-tert-butyl-m-cresols or
mono- or di-tertbutyl-p-cresol in the liquid phase in the presence
of a sulfuric acid catalyst.
[0006] Furthermore, Japanese Patent Application Laid-open No.
H5-51337 discloses a method for producing highly purified
m-tert-butylphenol, in which butyl groups of p-tert-butylphenol in
a mixture of m-tert-butylphenol and p-tert-butylphenol are
selectively removed in the liquid phase in the presence of a
catalyst consisting of an active white clay and a small amount of a
basic substance such as an alkaline metal.
[0007] However, the reactions in these known methods for removing
butyl groups take place in the liquid phase and have to be carried
out in the presence of a strong acid, such as sulfuiric acid and
sulfonic acid, and at a high temperature since butyl groups bonding
with a phenol compound at the para position and meta position in
particular are more difficult to remove than those bonding at the
ortho position. Thus, the equipment for the reaction, such as the
reaction vessel, tends to corrode so that the material for the
equipment is limited. Further, the recovered isobutylene contains
impurities primarily attributed to the catalyst so that the
isobutylene is not pure enough to reuse as raw material isobutylene
for a butylation reaction and another purification is required.
[0008] In removing butyl groups in the presence of a solid acid
catalyst such as active white clay, the reaction time is long and a
catalyst filtration process is required. Furthermore, the recovered
isobutylene causes similar problems as mentioned above for organic
acid catalysts.
SUMMARY OF THE INVENTION
[0009] Accordingly, the present invention is intended to solve the
abovementioned problems associated with conventional methods for
removing butyl groups in the liquid phase. Namely, an object of the
present invention is to provide a method for easily removing butyl
groups from butylphenol compounds, in particular, p- and
m-tertbutylphenols in a high yield on an industrial scale. Another
object of the present invention is to provide a method for removing
butyl groups from butylphenol compounds in which the recovered
isobutylene is of high purity and does not require another
purification to reuse as raw material isobutylene for a butylation
reaction or the like.
[0010] The present invention provides a method for removing butyl
groups from a butylphenol compound, characterized in that the
butylphenol compound in the gas phase is brought into contact with
a solid acid catalyst while heating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Examples of the butylphenol compound used in the present
invention include those in which the tert-butyl group is bound to
phenol or an alkyl phenol compound such as o-cresol, m-cresol,
p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol,
3,4-xylenol, 3,5-xylenol. More precisely, they include
o-tert-butylphenol, m-tert-butylphenol, p-tert-butylphenol,
2,4-di-tert-butylphenol, 2,5-di-tert-butylphenol,
2,6-di-tert-butylphenol, 2-tert-butyl-p-cresol,
2,6-di-tert-butyl-p-creso- l, 2, 4-di-tert-butylmetacresol, and
6-tert-butyl-2,4-xylenol. In particular, p-tert-butylphenol,
m-tert-butylphenol, 2,4-di-tert-butyl-m-cresol, and
2,6-di-tert-butyl-p-cresol are preferable.
[0012] A solid acid of strong acidity is preferable as a solid acid
catalyst used in the present invention. More precisely,
silica-alumina catalyst or alumina catalyst is used. A preferable
silica-alumina catalyst is a synthetic amorphous silica-alumina
catalyst. Its SiO.sub.2/Al.sub.2O.sub.3 ratio is not specifically
limited. Any readily available alumina-containing product having an
alumina content from as low as about 12% to as high as about 25%
can be used. The form of these catalysts upon use is not limited.
As an alumina catalyst, .gamma.-alumina is preferably used.
However, cylindrically molded particles having an approximate
dimension of (height: 1-10 mm).times.(diameter: 1-10 mm) are used
because of less variation in the catalytic strength of the molded
particles and for other reasons.
[0013] The reaction to remove butyl groups is carried out by
bringing a butylphenol compound in the gas phase into contact with
a solid acid catalyst while heating. The butylphenol raw material
used in the present invention can be a single butylphenol compound,
a mixture of butylphenol compounds or a mixture of phenol compounds
containing a butylphenol compound as the major component.
[0014] Examples of these mixtures include butylphenol compounds
which are present in the reaction system upon the production of
4,4'-biphenol by removing butyl groups from crude or purified
3,3',5,5'-tetra-tert-butyl-b- iphenol produced by dimerizing
2,6-di-tert-butylphenol by oxidation, or butylated cresol compounds
upon the production of highly purified m-cresol and p-cresol by
reacting a mixture of m- and p-cresols with isobutylene, isolating
the resulting corresponding butylated cresols, and removing butyl
groups from them. Further, the butylphenol raw material can be
diluted with an aromatic hydrocarbon, water, nitrogen or the like
for the reaction. These diluting agents can be mixed in advance
with the butylphenol raw material and then fed into a reaction
vessel, or fed into the vessel separately. Phenol is preferable as
a diluting agent because it lowers the coagulation point of the
butylphenol raw material and has no adverse effect on the reaction.
Preferably, phenol is admixed in advance with the butylphenol raw
material, and then fed into the reaction vessel.
[0015] The amount of diluting agent to be added is generally
between 30 wt % and 70 wt %/70 wt % and 30 wt % for
phenol/butylphenol compound.
[0016] Further, a small amount of water is preferably added as a
diluting agent to moderate the reduction in the removed rate of
butyl groups due to deterioration of the solid acid catalyst with
time (decoking). This water is preferably fed into the reaction
vessel separately from the butylphenol raw material or a mixture of
the butylphenol raw material and phenol because water and the
butylphenol raw material are immiscible.
[0017] The reaction temperature increases if too much water is
added, but the decoking effect by adding water will not occur if
too little water is added. Accordingly, the preferable amount of
water is 30-50 wt % of the supplied liquid (butylphenol raw
material+phenol+water).
[0018] The type of gas phase reaction mode is not specifically
limited and any gas-solid catalyst reaction vessel, such as a
batch, fixed-bed or fluid-bed mode reactor can be used. However,
fixed-bed mode is preferable for reasons economy, including low
equipment cost. The reaction temperature is in the range of
200.degree. C. to 500.degree. C., preferably 200.degree. C. to
400.degree. C., more preferably 250.degree. C. to 350.degree. C.
because reduction in the removed of butyl group is small if the
temperature is lower than 200.degree. C. and the catalyst function
decreases if the temperature is higher than 600.degree. C. The
reaction pressure is not specifically limited, however a normal
pressure is preferable.
[0019] Generally, at the abovementioned range of temperature and
pressure, the reaction for removing butyl groups is completed
instantly upon gas phase contact with the catalyst.
[0020] In the present invention, the method for feeding a raw
material mixture into the reaction vessel is not specifically
limited. For example, the mixture can be fed via a raw material
preheating vessel and a vaporization vessel from the upper part of
the reaction vessel. The feed rate is preferably in a range of
0.01-10 g/cc/hr, more preferably 0.1-1.0 g/cc/hr, as the liquid
headspace velocity (LHSV) for the butylphenol raw material
standard. If the feed rate is too slow, the amount of by-products
increases due to isomerization reaction of the butylphenol raw
material. If the rate is too fast, the butyl group removed rate
decreases.
[0021] Water, a diluting agent, which can be fed to the reaction
vessel separately from the raw material is generally fed to the
reaction vessel as steam via a vaporization vessel in the same
manner as described for the raw material mixture. The feed rate is
about 0.2-0.4 g/cc/hr as the liquid head space velocity (LHSV).
[0022] For a fixed-bed mode reactor, the vessel is preferably
filled in advance with a molded solid acid catalyst. Generally,
activation treatment is preferably carried out with an inert gas,
such as nitrogen gas, at 250-500.degree. C. for about 5 hours
before the reaction for removal of water from and activation of the
catalyst.
[0023] Under the abovementioned conditions, butyl groups are
readily removed from a butylphenol compound such as a
tert-butylphenol compound by bringing the compound into contact
with the abovementioned catalyst, and isobutylene and phenol
compounds can be isolated. The reaction product is condensed
liquefied by using a cooling tube or the like to recover phenol
compounds lacking butyl groups at o-, m- and p-positions at a
highly selective rate as well as highly purified isobutylene.
[0024] The butyl group removal rate is generally about 80-95% in
the early stages of the reaction but decreases as the reaction time
lapses. Further, the recovered isobutylene generally is of a
90-100% purity, occasionally contains a trace amount of isobutane
or the like as a by-product, but does not contain corrosive harmful
trace impurities such as sulfur compounds. Therefore, this
isobutylene can generally be used as is without further
purification as an isobutylene raw material, for example, for
butylation of phenol compounds.
[0025] Further, in the present invention, the activity of the
catalyst is slow so that the reaction for removing butyl groups can
be continued, for example, for more than 400 hours on an industrial
scale and the catalyst can be easily reactivated by regeneration.
Further, the purity of the recovered isobutylene does not decrease
when produced using this regenerated catalyst.
EXAMPLE
[0026] The present invention will be explained more in detail by
the following examples.
[0027] In the present invention, the butyl group removed rate is
expressed by the following formula. Butyl group removal rate
(%)={(number of moles of butyl groups in the reaction
product)/(number of moles of total phenols in the reaction
product)}/{(number of moles of butyl groups in raw
material)/(number of moles of total phenols in raw material)}
Example 1
[0028] A vertical reaction tube (diameter: 1/2 inch, length: 40 cm)
equipped with a raw material preheating vessel, vaporization vessel
and Dimroth condenser for reaction products was used. An amorphous
silica-alumina catalyst in the form of cylindrically molded
particles 25 ml (N632HN, a product of Nikki Chemical Corp.) was
filled into this reaction tube and heated under a nitrogen gas flow
to activate the catalyst. Then, a raw material mixture consisting
of a 70 wt % butylphenol composition containing 98 wt %
p-tert-butylphenol and 30 wt % phenol was fed via the preheating
vessel and the vaporization vessel from the top of the reaction
tube. The reaction was carried out at 280.degree. C. under normal
pressure at a LHSV of 0.49 hr.sup.-1 for the raw material mixture
(at a LHSV of 0.34 hr.sup.-1 for p-tert-butylphenol standard).
[0029] After 45 hours of reaction, the liquid reaction product and
reaction product gas were sampled and analyzed by gas
chromatography. Results showed that the reaction product comprised
90.5 wt % phenol, 0.3 wt % o-tert-butylphenol, and 8.8 wt %
p-tert-butylphenol, and the butyl group removed rate was 90.5%.
[0030] On the other hand, the reaction product gas was isobutylene
having a purity of 98.8 wt %, which did not contain any corrosive
compounds such as sulfur oxides.
Example 2
[0031] An experiment was carried out as described in Example 1,
except that a butylphenol composition containing 75 wt %
p-tert-butylphenol (PTBP), 9 wt % m-tert-butylphenol (TBP), and 3
wt % o-tert-butylphenol (OTBP) was used instead of the butylphenol
composition containing 98 wt % p-tert-butylphenol, and the reaction
was carried at a LHSV of 0.71 hr.sup.-1 for the raw material
mixture (at a LHSV of 0.5 hr.sup.-1 for p-tert-butylphenol
standard).
[0032] After 30 hours of reaction, the liquid reaction product was
sampled and analyzed by gas chromatography. Results showed that the
reaction product comprised 82 wt % phenol, 9.7 wt % PTBP, 7.3 wt %
MTBP, and 0.7 wt % OTBP, and the butyl group removed rate was 81%.
The raw material mixture was further continuously fed to carry out
the reaction under the abovementioned conditions. After 360 hours
of reaction, the liquid reaction product and reaction product gas
were sampled and analyzed by gas chromatography. Results showed
that the reaction product comprised 66 wt % phenol, 23.7 wt % PTBP,
8.6 wt % MTBP, and 0.7 wt % OTBP, and the butyl group removed rate
was 61%.
[0033] On the other hand, the reaction product gas was isobutylene
having a purity of 99.8 wt %, which did not contain any corrosive
compounds such as sulfur oxides.
Example 3
[0034] An experiment was carried out as in Example 2, in which in
addition to the raw material mixture, water was fed to the reaction
tube through the preheating vessel and the vaporization vessel into
the top of the reaction tube, from a feed tube different from that
for the raw material mixture. The LHSV for the raw material mixture
is 0.71 hr.sup.-1 (at a LHSV of 0.34 hr.sup.-1 for
p-tert-butylphenol standard) and the LHSV for water was 0.3
hr.sup.-1. Otherwise, the experiment was carried out in the same
manner as described in Example 2.
[0035] After 7 hours of reaction, the liquid reaction product was
sampled and analyzed by gas chromatography. Results showed that the
butyl group removed rate was 62%. On the other hand, the reaction
product gas was isobutylene having a purity of 99.8 wt %, which did
not contain any corrosive compounds such as sulfur oxides.
Example 4
[0036] The reaction was carried out as described in Example 3, in
which feeding of the raw material mixture and water to the reaction
tube was stopped when the butyl group removed rate became less than
60%, and the catalyst was regenerated by increasing the temperature
up to 500.degree. C. first under a nitrogen flow, then under air.
Then, the reaction for removing butyl groups as described in
Example 3 was repeated. Immediately after the start of the
reaction, the liquid reaction product was sampled and analyzed by
gas chromatography. Results showed that the butyl group removed
rate was 85%.
[0037] The raw material mixture was further continuously supplied
to carry out the reaction under the abovementioned conditions.
After 500 hours of reaction, the liquid reaction product and
reaction product gas were sampled and analyzed by gas
chromatography. Results showed that the butyl group removed rate
was 60%. On the other hand, the reaction product gas was
isobutylene having a purity of 99.8 wt %, which did not contain any
corrosive compounds such as sulfur oxides.
Example 5
[0038] An experiment was carried out as described in Example 1, in
which a raw material mixture consisting of a 72 wt %
butyl-paracrezol composition containing 97.5 wt %
2,6-di-tert-butylphenol and 28 wt % phenol was used instead of the
raw material mixture consisting of the 30 wt % butylphenol
composition containing 98 wt % p-tert-butylphenol and 30 wt %
phenol.
[0039] The reaction was carried out as described in Example 1,
except that the LHSV was 0.49 hr.sup.-1 for the raw material
mixture (at a LHSV of 0.35 hr.sup.-1 for
2,6-di-tert-butyl-paracresol standard).
[0040] After 45 hours of reaction, the liquid reaction product and
reaction product gas were sampled and analyzed by gas
chromatography. Results showed that the reaction product comprised
42 wt % phenol, 46 wt % p-cresol, 5 wt %
2,6-di-tert-butyl-paracresol, and 3 wt % 2-tert-butyl-p-cresol, and
the butyl group removed rate was 92.8%. On the other hand, the
reaction product gas was isobutylene having a purity of 99.0 wt %,
which did not contain any corrosive compounds such as sulfur
oxides.
Comparative Example
[0041] A butylphenol composition (250 g) containing 98 wt %
p-tert-butylphenol and 0.5 g of p-toluene sulfonic acid, a
catalyst, were placed in a four-naked flask fitted with a stirring
device, a thermometer and a column filled to a height of 10 cm with
stainless steal helipack, and then heated.
[0042] After reaction at 220.degree. C. for about 10 hours, 137 g
of phenol were distilled off The butyl group removed rate was 80%.
On the other hand, results of gas chromatography showed that the
reaction product gas is isobutylene, which contained 0.1 wt %
SO.sub.2.
[0043] Further, after the reaction, 25 g of liquid was left at the
bottom of the flask. The liquid was strongly acidic with a pH of
2.
[0044] Effectiveness of the Invention
[0045] In the method for removing butyl groups from a butylphenol
compound according to the present invention, butyl groups are
removed by bringing the butylphenol compound in the gas phase into
contact with a solid acid catalyst so that the reaction can be
instantly completed and the butyl group removed rate is high, which
can easily applied to continuous process on an industrial scale.
Furthermore, the recovered isobutylene is of high purity and does
not contain any harmful trace impurities, such as sulfur compounds,
so that it can be reused as an isobutylene raw material for
butylation of phenol compounds.
[0046] Further, the activity of the catalyst decreases slowly, so
that a continuous reaction for removing butyl groups for more than
400 hours is possible on an industrial scale, and the catalyst can
be easily reactivated by regeneration. Further, the use of this
regenerated catalyst does not lower the purity of the recovered
butylene.
* * * * *